Improvement in wood-screws



"r. a. snow.

WOOD-SCREW.

Patented Ian. 18, 1876.

UNITED STATES PATENT QFFIGE.

THOMAS J. SLOAN, OF NEW YORK, N. Y.

IMPROVEMENT IN WOOD-SCREWS.

Specification forming part of Letters Patent No. 172,35l, dated January18, 1876; application filed July 10, 1875.

To all whom it may concern Be it known that I, THOMAS J. SLoAN, of thecity, county, and State of New York, have invented an Improvement inWood-Screws, of which the following is a specification:

The object of this invention is to provide a wood-screw which may bedriven either by a common square-ended screw-driver or by a driverconstructed especially for it, the former permitting the use of thescrew, under ordinary conditions, with as great efficiency as ispossible with the common screw, and the latter enabling it to be drivenunder conditions in which the ordinary screw-driver would slip from thegroove in the head of the screw, and, as frequently occurs, mar orfracture the head, injuring the symmetrical appearance of the head, andin many cases destroying the utility of the screw.

The invention consists in a screw constructed with a groove or nickhaving the usual depth at the center of the head and deepened outwardly,with sloping surfaces, to the sides of the head, whereby, as may bepreferred, or as occasion may demand, a notched orspecially-"constructed driver may be applied to the screw, to exert agreat degree of force in driving the same without danger of slipping, ora common screw-driver employed to turn the screw in the ordinary manner.

Figure 1 is a partial longitudinal section of a wood-screw madeaccording to my invention. Fig. 2 is a side view of the same. Fig. 3 isa partial section of a modification of the same. Fig. 4 is a top view ofthe same, and Fig. 5 is a side view of the driver more especiallydesigned for use therewith.

The shank A and head B, except as hereinafter particularly specified,are of the usual form and structure, and therefore require no specialdescription.

The nick or groove of the head of the screw is represented at a, but,instead of being flat or straightbottomed, as in the common woodscrew,or sloping laterally from a point fiush with the outer surface, as inscrews hitherto proposed for use in connection with indentedscrew-drivers, the groove a in my aforesaid screw has at its center 0the depth of the usual nick of the common screw, and, sloping laterallyoutward. and downward from this point to the sides of the head, (openingat or through the said sides,) as shown at f, is much deeper at its endportions than at its center. Such being the character of the groove, thenotched driver shown in Fig. 5 may be inserted, and, holding not only atthe center, but with a deeper and firmer hold at the ends of the groovethan is possible with the straight-bottomed groove, enables a greaterpurchase to be had upon the screw than is possible with screws made withthe straight bottomed grooves. Moreover, the groove in my aforesaidimproved screw, having at its center a depth equal to that of the usualstraight-bottomed groove, permits, in the absence of the indenteddriver, the insertion and use of the ordinary straight ended driver,with just-as much convenience and efficiency as is possible with thecommon wood-screw, and, furthermore, even with the ordinary driveraforesaid, my improved screw may be applied in use with greaterefficiency and facility than the common screw, for the reason that theslopes f, in connection with the depth of the groove at the center 0permits the driver to be held at a greater angle to the axis of thescrew, without displacement from the groove, than would be possible withthe common screw, or, for that matter, with lateral grooves or notchesstarting flush with the outer surface of the head, and designed for thereception of aforked or indented driver.

What I claim as my invention is- The wood-screw constructed with thegroove a, having at its center 0 the depth of the nick of the commonwood-screw, and deepened with sloping surfaces to and through the sidesof the head, substantially as and for the purpose herein set forth.

THUS. J. SLOAN.

Attest WM. EDWARDS, ELBERT F. DEARBORN.

